The engine, rated at 33,000 lb. thrust, has accumulated 120 hours since beginning tests at P&W’s West Palm Beach, Fla., test site in early December. The unit concluded acoustic tests on April 10, and following installation work at P&W’s Mirabel, Canada, site, is expected to begin flight tests in June.

A second engine is undergoing structural tests and is poised for crosswind evaluations that could determine whether the variable area fan nozzle (VAN) is retained on the P&W-powered A320NEO. Bob Saia, VP of P&W next generation products family, says the decision could be made in about two months.

The feature, which dynamically alters the exit nozzle area for different phases of flight to maintain blade stability, was deleted from the smaller PW1500G engine for Bombardier’s CSeries late last year. P&W decided to drop the VAN when tests of an upgraded fan blade revealed the stiffer unit delivered the same performance while maintaining adequate flutter margin without the need for a variable nozzle.

Although the VAN also offers potential fuel burn savings, Saia says the baseline engine in both the CSeries and A320NEO will provide guaranteed fuel burn performance without the feature. The VAN adds weight and mechanical complexity, and although P&W designed it for minimum impact on maintenance, the company’s clear preference is that the system also be deleted from the Airbus engine. At the same time, P&W says the extensive development work on the two different VAN designs that were created for the CSeries and the A320NEO will be useful in future as a possible hedge against rising fuel costs and noise regulations.

The third NEO engine will begin high-pressure spool tests next month, while a fourth PW1100G has begun endurance testing at P&W’s Manitoba icing facility in Canada. The first four engines are expected to amass 1,000 test hours collectively in the run-up to certification testing, which is due start in “two to three months,” says Saia.

P&W’s update on NEO engine testing comes as the engine maker receives a contract from Hawaiian Airlines for its fleet of up to 25 A321NEOs. The airline, which firmed plans for 16 aircraft plus nine options in late March, is due to take the first NEO in 2017. P&W says selection of the geared turbofan for the Hawaiian fleet is evidence of a growing preference by operators for the PW1133G engine on the long-haul, higher-capacity A321 over the competing CFM Leap-1A powerplant. Total A320NEO family orders now stand at almost 2,070, of which some 416 are for the A321NEO version.